JPH052937Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention relates to a nip pressurizing device for forming a fixing nip in a fixing device of a copying machine or the like.

[Conventional technology]

When forming a nip (NIP) between a pair of rolls in a fixing device, for example, when a heat roll is fixed and the pressure roll is moved to form a nip between the heat roll and the pressure roll, There are a method of applying pressure using a two-stage link mechanism and a method of applying pressure using a single-stage link mechanism.

In the case of a structure using a two-stage link mechanism, it is possible to reduce the force generated by the pressurizing spring portion against the load at the nip. That is,
Even if the force generated in the spring part is relatively small, the load at the nip can be increased by using two stages of links, and the required load can therefore be satisfied with a small spring force. Especially in Wanilo type or shell type copying machines, the upper half of the machine is closed against the force of the pressurizing spring, so the force generated by the spring is relatively small. The fact that only a small nip is required allows the operator to perform the closing operation with a small amount of force even if the model requires a large nip load, which is convenient in terms of operability in the event of a jam or other trouble.

However, in the case of a two-stage link, since the link mechanism is two-stage, there are drawbacks such as increased costs compared to the case of a single-stage link.
On the other hand, in the case of a structure using a single-stage link mechanism, this does not occur, and the mechanism is simple and
It is useful when effective use of space is required, and in this respect it is particularly advantageous for small and simple alligator types. It is not possible to make the force generated by the spring part significantly smaller than the load at the nip, and the force generated by the pressurizing spring part becomes relatively large.

When the force generated in the spring part is large,
The lever that holds the pressure roll that is moved during pressurization tends to tilt, leading to a situation where the nip is not properly engaged. In addition, in the case where there is a clearance fit between the pressure roll shaft and the ball bearing for ease of assembly, ease of replacement, and cost,
In other words, if the lever is fitted with a gap, the shaft will be scraped if the lever is tilted. This scraping of the shaft causes rattling, scrapes get into the bearings and cause rotational problems, and the nip becomes improper, resulting in a decline in image quality. As a countermeasure, it is possible to prevent the lever from tilting by crimping a sintered bearing on the rotating part of the lever, but this is not perfect, and especially when the loose fit is used as described above, it is possible to prevent the lever from tilting. This is insufficient as a countermeasure.

[Problem that the invention attempts to solve]

This invention is an attempt to solve the problem that when applying pressure using a link mechanism, the lever of the link mechanism tilts, making it difficult to form a nip properly.

[Means and actions for solving problems]

For this reason, this invention places a tube between the spring that pressurizes the roll to form a nip and the screw inserted into the spring, and the lower end of the tube is the lever in the link mechanism for screwing the screw together. The lever of the link mechanism holding the roll is prevented from tilting by providing the roll so that it reaches the bending part.

〔Example〕

An embodiment of this invention will be described below based on the drawings.

1 and 2 show an embodiment of this invention, which is applied to a fixing device in a Wanilo type copying machine having a pair of heat rolls and a pressure roll.

FIG. 1A is a side view of the fixing device, and FIG. 1B is a plan view thereof with some members omitted, in which 1 is a pressure roll, 2 is a heat roll, 3 is a shaft of the pressure roll 1, 4 is a ball bearing, 5
is a lever, and the lever 5 holds the ball bearing 4 contained in the shaft 3 of the pressure roll 1. Above pressure roll 1
There may be a loose fit between the ball bearing 4 and the ball bearing 4.

6 is a sintered bearing, and 7 is a stud.The sintered bearing 6 is caulked on one end side of the lever 5 (on the right side in the drawing), and enters the stud 7 for holding the lever rotation center S, and is attached to this stud 7. An E-ring 8 is inserted to prevent the lever 5 from coming off.

The other end side (left side in the drawing) of the lever 5 has the following configuration. That is, in the illustrated case, the link has a one-stage structure, and a compression spring 9 for pressurizing is provided at the other end side of the lever 5 that constitutes the link mechanism, and a compression spring 9 is further provided.
A tube 10 is inserted inside. As shown in FIG. 1A and FIG. 2, the screw 11 is
The tube 10 in the compression spring 9 is passed through the hole 13 in the bent portion 12a of the fixed plate 12, and is screwed into the female screw portion of the bent portion 5a of the lever 5. The tube 10 is for preventing the lever 5 holding the pressure roll 1 from tilting.

In FIG. 1B, illustration of the heat roll 2 is omitted, and although only one side of the pressure mechanism is shown in the figure, the opposite side has the same configuration. That is, the one-stage link mechanism including the tube 10 described above is provided on both sides of the pressure roll 1 in the axial direction.

In this example, the heat roll 2 is moved up and down by opening and closing the cover of the copying machine. When you open Wanilo,
The lever 5 is rotated clockwise in FIG. 1A with the stud 7 as a fulcrum by the force of the compression spring 9, and the pressure roll 1 moves upward, but the heat roll 2 It is lifted upward together with roll 1. Therefore, when the roll is opened, the heat roll 2 simply rests on the pressure roll 1 due to its own weight.

Paper jam removal is performed in this state.
The operator manually lifts the free heat roll 2 a little further upward and removes it.

The nip is formed when the upper half of the fuselage is closed from the open state of the nips.

That is, when the operator pushes down the upper half of the machine in the direction of closing, a force is applied to push the heat roll 2 downward, and from then on, the pressure roll 1 and the lever 5 are moved via the heat roll 2. It will be pushed down against the force of the compression spring 9. When the cover is completely closed, the upper half of the body is locked to the lower half, and the heat roll 2 is regulated by the locked upper half, so its upward position is fixed. On the other hand, since the pressure roll 1 is pressed from below by the force of the compression spring 9 via the lever 5 against the heat roll 2 whose upward position is regulated in this way, the pressure roll 1 is pressed against the heat roll 2 whose upward position is regulated in this way. The shear roll 1 comes into contact with the heat roll 2 under a predetermined load due to the force of its compression spring 9, thereby forming a nip. Regarding the load at the nip, in the case shown, a one-stage link mechanism is used, and the position of the shaft 3 of the pressure roll 1 is between the stud 7, which is the rotation center S on one end of the lever 5, and the compression on the other end of the lever 5. Since it is located approximately midway between the spring 9 and the spring 9, the force is approximately twice that of the compression spring 9, and conversely, the compression spring 9 needs to generate approximately 1/2 the force for the desired load. Become.

In this way, pressure is applied to the pressure roll 1 to form a nip between the heat roll 2 and the pressure roll 1. In this case, as shown in FIGS. 1A and 2, the tube 10 is Since we have set up
The levers 5 on both sides of the pressure roll 1 in the axial direction are prevented from tilting during nip formation.

To further explain this with reference to Figure 3,
FIG. 3 is a comparative example in which the tube 10 is not provided in the compression spring 9 for pressurization. If the tube 10 is not provided as shown in the figure, the lever 5 cannot be moved in the left-right direction or tilted. It will happen. As a result, galling occurs in the shaft 3 of the pressure roll 1 and the ball bearing 4. In addition, the bent portion 1 of the plate 12
Galling also occurs in the hole 13 of 2a and the screw thread of the screw 11, and if the nip is pinched in the middle, the nip cannot be formed properly. In the worst case, the compression spring 9 may enter the hole 13 of the plate 12, and in such a case, the original function of the compression spring 9 for pressurizing is to press the pressure roll 1 to obtain a predetermined load. I can't stand it anymore.

On the other hand, if the tube 10 is inserted as in the pressure device shown in Figs. 1 in a plane perpendicular to the axis of FIG.

In this way, according to the above embodiment, when pressure is applied to the pressure roll 1 to form a nip between the heat roll 2 and the pressure roll 1, the pressure applied to the pressure roll 1 is It is possible to prevent the lever 5 holding the pressure roll 1 from tilting by using a one-stage link mechanism and providing a tube 10 in the compression spring 9 for pressurization. Even if the lever 5 is a one-stage link and the ball bearing 4 and the shaft 3 of the pressure roll 1 are left in a loose fit from the viewpoint of ease of assembly, ease of replacement, and cost, the lever 5 may tilt and the nip There is no problem that the shaft 3 does not engage properly, and there is no inconvenience caused by the shaft 3 being scraped.
Since the tube 10 is inserted up to the bent part 5a of the lever 5, the hole 13 of the plate 12 and the screw thread of the screw 11 do not come into direct contact with each other, preventing galling. It is also a hindrance to enter the age of 13.

Regarding the material of the tube 10, for example, when the fixed plate 12 is made of sheet metal (SPCC, SPG (zinc copper plate), etc.), POM (polyaceol ), those made of resin such as nylon are suitable.
Although this does not preclude the use of other materials,
In particular, when the resin is used as described above, unlike conventional cases where the shaft 3 is scraped due to the inclination of the lever 5 in the case of a clearance fit, and noise is also generated, this does not occur. Even if the shaft 3 is left in a loose fit, it is possible to easily prevent the shaft 3 from being scraped or making abnormal noises.

Furthermore, since the tube 10 is inserted, by regulating the length of the tube, the nip width and the magnitude of the load that forms the nip can be regulated, making it easier to adjust the nip width and the magnitude of the load. You can also. That is, compared to the case shown in FIG. 3, the desired magnitude of the load required corresponds to the depth to which the screw 11 is screwed into the bent portion 5a of the lever 5. In the manufacturing process, it is necessary to screw each product to a certain depth. However, in the case of Figure 3, there is no guideline, so
The worker screws the screws together to the approximate point, measures the load at any time, and if the load is insufficient, tighten screw 1.
It is necessary to repeatedly perform adjustment work such as screwing in part 1 a little further and measuring the load again.

On the other hand, when the tube 10 is used, the depth of screw engagement of the screw 11 can be regulated by the length of the tube 10. Therefore, if the tube 10 is prepared with a length corresponding to the screwing depth when the required load is obtained, the operator does not have to carry out the above-mentioned troublesome work each time. The time-consuming adjustment process described above can be eliminated, and the screw 11 can be screwed in until it reaches the state shown in FIGS. 1A and 2.

Further, in the case of the above-mentioned embodiment device, since a one-stage link mechanism is used, the mechanism is simple and requires only a small space. Since there is a clearance fit between the shaft and the ball bearing, it is easier to assemble compared to a configuration in which the ball bearing and shaft are fitted together by press fitting, and replacement is also easier because the two can be easily separated. For example, when replacing only the ball bearing, it is not enough to replace only the ball bearing, which causes problems such as replacing the assembly and increasing costs, but there is an additional advantage that such problems do not occur. .

Although this invention has been described with respect to the above-mentioned specific embodiment, it is not limited thereto, and various modifications are possible.

[Effect of idea]

As described above, according to this invention, it is possible to prevent the lever holding the roll for forming the nip from tilting, so the nip can be formed properly, and the nip may not be applied properly. It has the advantage of being able to eliminate inconveniences such as loss of performance. In addition, according to the present invention, the tube is provided so that its lower end reaches the bending part of the lever for screwing the screw, so that the hole in the fixing plate through which the screw is passed is connected to the screw. This has the effect of preventing the occurrence of galling since the screw threads do not come into direct contact with each other, and also preventing the pressurizing spring from being inserted into the hole. Moreover,
By regulating the tube length, it is possible to regulate the magnitude of the load that causes a nip to form, and the process of adjusting the magnitude of the nip load can be facilitated.

[Brief explanation of the drawing]

1A and 1B are a side view and a partially omitted plan view of a fixing device showing an embodiment of the invention, FIG. 2 is an explanatory diagram of the main parts of the embodiment, and FIG. 3 is a comparative example. It is a figure provided for explanation. Explanation of symbols, 1...pressure roll, 5...
Lever, 7... stud, 9... compression spring, 10... tube, 12... plate.

Claims (1)

[Scope of utility model registration request] This is a device that pressurizes the roll of the fixing device using a one-stage link mechanism to form a nip, and the tube is placed between a pressurizing spring and a screw inserted into the spring, and the lower end of the tube is 1. A nip pressurizing device for a fixing device, characterized in that the nip pressurizing device for a fixing device is provided so that the lever reaches a bent portion in a link mechanism for screwing together a screw.